EFFECT OF HEAT TREATMENT ON THE STRUCTURE AND MECHANICAL PROPERTIES OF COLD WORKED AL-3MG-2SI 0.5NI ALLOYS SYSTEM

Abstract

This study examined how heat treatment affected the mechanical characteristics and composition of the Al-3wt%Mg-2wt%Si-0.5wt%Ni alloy. The permanent die-casting technique was used to prepare the samples, which were then machined to the necessary dimensions for the structural analysis and mechanical test. A 100KN JPL tensile strength tester (Model: 130812), a dynamic hardness tester, and an impact testing machine (Model: U1820) were used to determine the mechanical properties under study, including percentage elongation, ultimate tensile strength, hardness, and impact strength. Meanwhile, an optical metallurgical microscope (Model: L2003A) and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) were used to study the microstructures of the alloys. According to the microstructural examination, the control sample had coarse micro segregation of the intermetallic complex (MgSi2). The solution heat-treated samples showed the presence of fine intermetallic compound (MgSi2) grains dispersed uniformly. The results of the mechanical tests demonstrated that heat treatment greatly increased the alloy's ultimate tensile strength, impact strength, and percentage elongation. The presence of finely dispersed intermetallic compound (MgSi2) grains in the alloy structure served as a proxy for this. Heat treatment eliminated the micro-segregation of MgSi2 in the alloy structure by preventing solute redistribution of Mg, Ni, and Si. Because the alloy structure contained a coarse intermetallic compound (MgSi2), the control sample had the highest hardness value